Method for producing screen frame bars



April 17, 1956 Filed April 7, 1952 I I 22 24 26 28 3O 32 R- O- JOHNSON METHOD FOR PRODUCING SCREEN FRAME BARS ROBER 2 .ShGBtS-Sheet 1 VENTOR.

. JOHNSON BY WW ATTORN S United States Patent Ofiice 2,741,831 Patented Apr. 17, 19 56 METHOD FOR PRODUCING SCREEN FRAME BARS Robert 0. Johnson, Erie, Pa., assignor to Deh'oit Steel Products Company, Detroit, Micln, a corporation of Michigan Application April 7, 1952, Serial No. 281,011

3 Claims. (Cl. 29477.7)

The present invention relates to method for producing screen frame bars.

According to the present invention elongated or substantially continuous strip stock is rolled, welded, and subjected to a final rolling operation in a predetermined manner to produce a frame bar having a hollow box section and including a double walled channel located at one side of the box section.

It is an object of the present invention to provide a method for producing screen frame bars characterized in the provision of a welded joint between portions of the strip material at a predetermined point in the forming thereof.

More specifically, it is an object of the present invention to provide method for initially forming strip material into a hollow box section with both edge portions of the strip material extending first laterally from one corner of the box section and thence obliquely to form a partially completed channel at one side thereof. One extreme edge portion of the strip material is reversely bent in interlocking relation over the other edge thereof. At this time a weld is efiected between the edge portions of the strip material constituting the bottom wall of the channel. Finally, the outer wall of the channel is formed to final position or into parallelism with the adjacent side wall of the box section.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure l is a diagrammatic plan view of apparatus for carrying out the present invention.

Figure 2 is a diagrammatic side elevation of the mechanism shown in Figure 1.

Figure 3 is an enlarged end elevation of the pair of rolls at the first forming station showing the shape to which the strip material is formed by these rolls.

Figures 4-11 are fragmentary sectional views through the rolls provided at the second to ninth forming stations.

Figure 12 is a fragmentary transverse sectional view at the welding station.

Figures 13 and 14 are fragmentary transverse sectional views at the final two rolling stations.

Figure 15 is an enlarged fragmentary sectional view through a portion of a screen frame bar.

Referring now to the drawings, in Figures 1 and 2 there is shown a reel 10 mounted on a pedestal support 12 carrying a continuous supply of strip material 14 which may for example, be steel strip having a thickness of approximately .025" and a width of somewhat less than 2 /2". From this material a screen bar having the com pleted cross-sectional shape illustrated in Figure 14 is formed, the screen bar as illustrated having a width of approximately a height of approximately and a channel having a transverse width at its top of approximately The strip material 14 is advanced through a plurality of sets of rolls indicated generally at 16, 18,

2 20, 22, 24, 26, 28, 30, 32, 34 and 36, and thence throu a cut-off or flying shear indicated generally at 38 which severs the completed stock into desired lengths for fabrication into screen frames. Intermediate the pairs of rolls 32 and 34 is a welding station 40 including rolls 42 and 44 for effecting spot welds in a predetermined manner, as subsequently will be described.

Referring now to Figure 3, the set of rolls indicated generally at 16 forms the flat stock 14 to the crosssectional form illustrated in the figure. The rolls 18, 20, 22, 24, 26, 28, 30 and 32 progressively form the strip material to the cross-sectional shape illustrated in Figures 4-11. It will be observed in Figure 11 that the strip material has been formed to produce a hollow box section 46 having both edge portions of the strip extending laterally from one corner thereof in a direction parallel to the bottom wall of the box section 46, as indicated at 48, and thence obliquely upwardly as indicated at 50. At the same time one extreme edge portion of the strip has been reversely folded to overlap the other edge of the strip, as indicated at 52 to thereby interlock the edges of the strip. At this time the partially completed bar section passes between rolls 42 and 44 which are adapted to engage the straight extending edge portions of the strip which eventually become the bottom of the channel therein. The rolls 42 and 44 comprise the two electrodes of a seam type electric resistance welder, as is well understood in the art, and an electric current is intermittently supplied to the electrodes by means controlled by an appropriate timing device to efiect periodic spot welds. Excellent results are obtained when the frequency of supply of current is related to the rate of advance of strip material such that the spot welds are located approximately every four inches along the bar.

Following the welding operation, the partially formed bar passes through the rolls 34 and 36 which bend or form the portion 50 of the strip material upwardly into parallelism with the adjacent side of the box section 46, thus producing a channel 54 in the completed frame.

The particular relationship between the stage of completion of the frame bar and the welding operation leads to important advantages. With the frame bar in the condition illustrated in Figure ll, one edge of the strip has been crimped over the opposite edge as illustrated at 52. At this stage of the forming operation the bottom walls of the channel, as illustrated at 56 and S8 in Figure 15, are welded together, the weld being indicated diagramatically at 60. As a result of this operation the portions 56 and 58 of the strip are united in such a way that subsequent counterclockwise bending of the inclined portion 50 of the strip results in a bending of the stock about an axis located generally at 62. If the obliquely extending side wall 50 of the channel were bent counterclockwise, as seen in Figure 15, prior to completion of the weld 60, each of the edge portions of the strip would tend to bend about axes 64 and 66 respectively with the result that the edge 68 would be jammed into the crimped over portion 70 of the opposite edge with probable displacement of the adjacent wall of the box section resulting. However, with the weld holding the parts integral. the final shaping operation efiected by the rolls 34 and 36 does not have this effect and in the completed bar, as illustrated in Figure 14, the crirnped over portion retains the same relationship to the opposite edge as was initially established by the roll 32. There is thus avoided any relative movement between the bottom walls 56 and S8 and the exact desired width of groove is therefore maintained.

A second practical advantage of course is that the inclined wall portion 50 of the partially completed bar, as seen in Figure 12, provides more room for the flange 3 72 on the roll 42 to enter into the partially completed channel.

The drawings and the foregoing specification constitute a description of the improved method and apparatus for producing screen frame bars in such full, clear, conalso and exact terms as to enahle any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. The method of making a screen frame bar from flat strip material which comprises successively rolling the strip material to form a hollow box section with both side edge portions of the strip extending from one corner of the box section in surface to surface contact in parallelism with one side of the box section to provide a channel bottom, and thence obliquely upwardly to provide a channel side wall, forming the extreme lateral part of one edge portion over the other, then welding the portions of said strip forming said channel bottom together to prevent subsequent bending of the channel side wall from distorting the box section, and finally rolling the channel side wall into parallelism with the adjacent wall of the box section.

2. The method of making a screen frame bar from strip material which comprises forming the strip material into hollow box section with substantial portions of both edges of the strip material extending outwardly from one corner of the box section in parallelism with one side of the box section and in surface to surface relation, and thence obliquely upwardly to provide a channel bottom wall and a channel side wall inclined obliquely with respect to the bottom wall, then crimping the extreme part of one edge portion over the other to interlock the edge portions together, then welding together the parts of said edge portions forming the channel bottom wall to prevent subsequent bending of the channel side wall from distorting the box section, and thereafter forming the channel wall to extend perpendicular to the bottom wall and parallel to the adjacent wall of the box section.

3. The method as defined in claim 2 in which the forming and welding operations are performed progressively along the strip material.

References Cited in the file of this patent UNITED STATES PATENTS 1,304,594 Patscheider May 27, 1919 1,537,405 Bundy May 12, 1925 1,736,770 Cody Nov. 26, 1929 1,796,114 Meadowcraft Mar. 10, 1931 2,003,118 Mirfleld May 28, 1935 2,210,338 Quarnstrom Aug. 6, 1940 2,505,241 Gray Apr. 25, 1950 

